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US2225033A - Television system - Google Patents

Television system Download PDF

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Publication number
US2225033A
US2225033A US135621A US13562137A US2225033A US 2225033 A US2225033 A US 2225033A US 135621 A US135621 A US 135621A US 13562137 A US13562137 A US 13562137A US 2225033 A US2225033 A US 2225033A
Authority
US
United States
Prior art keywords
film
scanning
frame
area
image
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US135621A
Other languages
English (en)
Inventor
Condliffe George Edward
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EMI Ltd
Electrical and Musical Industries Ltd
Original Assignee
EMI Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by EMI Ltd filed Critical EMI Ltd
Application granted granted Critical
Publication of US2225033A publication Critical patent/US2225033A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
    • H04N3/36—Scanning of motion picture films, e.g. for telecine
    • H04N3/38—Scanning of motion picture films, e.g. for telecine with continuously moving film

Definitions

  • This invention relates to television-transmitting systems employing interlaced scanning and has particular reference to the transmission of continuously moving cinematograph films.
  • the first frame is scanned along linesin the order one, three, five, seven and so on,--the next frame being scanned along lines in the order two, four, six and so on, the odd and even sets of scanning lines being interlaced in the reconstituted picture.
  • an area of a film is scanned by an image of a scanning field of a cathode ray tube' in one position and subsequently by another image of the same field in another position displaced longitudinally with respect to the film.
  • one of said images is projected upon said area. while theother image is obscured, the latter image being projected upon said area, while the former is obscured after movement of said area through a distance equal to the longitudinal displacement of the scanning positions.
  • the cathode ray is caused to trace a scanning field, two images of which are formed by an optical system including mirror surfaces which reflect bothimages into the plane of the cinematograph filmto be transmitted.
  • An obturator serves alternately to obstruct one of said images while permitting the other to fall upon an area of the film to be scanned, and then to obstruct that image while the second image falls upon the same area of the film after it has traversed a predetermined distance.
  • Fig. 1 represents a piece of film showing the relative positions of the picture frames and scanning field,-and
  • Fig. 2 shows diagrammatically the relative positions of the component parts of apparatus for carrying out the invention. 4
  • a method of obtaining interlacing is shown in which it is assumed that the film l moves continuously downwardly, and a scanning beam, the trace '2 of which is shown, progresses upwardly during each scan.
  • the first scan of the interlace occurs during the period in which the film I (frame A) moves through a distance equal to half the height of one picture frame represented by the distance Y-O.
  • the scanning beam traverses area OY, so that, by reason of the scanning direction and the movement of the 9 film in the opposite direction, the entire film frame A is scanned.
  • the scanning beam is then blacked out while it is returned to a point on the line Z down the film equal to the height Y--Z of a whole picture frame from the point on the i line Y reached at the end of the first scan.
  • the second scan of the film frame A then takes place, this frame having by the commencement of the second scan moved from its initial position 30 picture, into the position between Z-Y.
  • the scanning beam then begins at point Z and scans the area Z--O. During this interval, the film has moved in the direction indicated by the arrow an amount equal to one-half film frame, so that frame A is scanned completely for the second time. Further movement of the beam over the area marked O-Y causes a first scanning of the next successive film frame. It will be seen, therefore, that during the time that the area ZY is scanned by the cathode ray beam, two complete film frames are traversed.
  • a cathode ray oscillograph tube 3 is provided with the-usual electron gun structure I4 and deflecting plates [6 and I8.
  • the deflecting plates (or alternatively deflecting coils) are energized by a deflection voltage generator .20 which constitutes a means for providing a scanning field of 405 lines, comprising two sets of 202 lines interlacing with each other.
  • the optical system includes an objective 4 and two mirrors 5 and 6 which are arranged at such an angle with respect to each other that they reflect two images of the scanning field 1 on the fluorescent screen of the cathode ray tube 3 into the path of movement of a continuously -moving cinematograph film 8 to be transmitted, one image 9 being displaced from the other image H] longitudinally of the film.
  • the film is driven by a motor 22 and a sprocket 24 at the rate of 25 picture frames per second.
  • the idler 26 directs the film from a reel (not shown) to the scanner.
  • An obturator II is arranged between the mirrors and a gate, not shown in the drawing, but through which the film ,passes and serves to permit the image 9 of the scanning field 1 to fall upon the moving film 8 while the image H3 is obscured. Movement of the obturator H causes the image 9 to be obscured and permits the image In to fall upon the moving film, the direction of movement of which is indicated by the arrow l2.
  • Each image of the scanning field is arranged to occupy half the area of a picture frame.
  • the distance d in the drawing represents the height of a picture frame, the image will be equal to .d in height.
  • the relation between the speed of movement of the film, the movement of the obturator and the frame scanning frequency of the cathode ray tube is such that during the period of of asecond in which the film isexposed to the image 9 of the scanning field, the film moves through a distance equal to half a picture frame and, due to the opposite movement of the scanning beam, a whole picture frame is scanned.
  • the obturator I l is then actuated to obscure the first image 9, and the image 10 will then scan the same picture area or frame in another set of scanning lines interlacing with the first set Since the motor 22 is driven from the deflection voltage generator 20, the film must move in synchronism with the scanning rate.
  • the amplitude of the frame scanning saw-tooth wave form is adjusted to ensure that in conjunction with the film movement the image of the scanning spot will traverse a whole film frame in ,4 of a second.
  • the image of the scanning field at 9 or ID is equal in height to half the height of a picture frame.
  • a television transmission system for scanning cinematograph film wherein the film moves continuously during scanning and wherein each film frame is scanned twice comprising means for producing a beam of radiant energy adapted for scanning a fluorescent area in a line-for-line Y manner, means for producing a separate image of each half of the scanned area, the images being directed upon the film and slightly displaced longitudinally with respect thereto by an amount equal to an odd number of half lines, and means means for electronically scanning a fluorescent area to produce a scanning light source area, means for producing two separate images of each half of the scanned area, the images being directed upon the film and each slightly displaced longitudinally with respect thereto by an amount equal to one half line and a number of whole lines, and means for moving the film at a uniform rate in a direction opposite to the scanning direction, therate of film frame movement being equal to the area scanning rate.
  • a television transmitting system for scan- ..ning cinematograph film wherein the film moves continuously during scanning and wherein each film frame is scanned twice comprising means for producing a beam ofradiant energy adapted for scanning a luminous area in a line-for-line manner to produce a scanning beam of light, means for producing a separate image of each half of the scanned area, the combined heights of the images being equal to one film frame, means for directing the images upon the film and slightly displaced longitudinally with respect thereto by an amount.
  • the film frame speed being equal to the area scanning speed, whereby two adjacent film frames are scanned for each scanning of said area.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Details Of Television Scanning (AREA)
  • Facsimile Scanning Arrangements (AREA)
US135621A 1936-04-09 1937-04-08 Television system Expired - Lifetime US2225033A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB10429/36A GB475032A (en) 1936-04-09 1936-04-09 Improvements relating to television systems

Publications (1)

Publication Number Publication Date
US2225033A true US2225033A (en) 1940-12-17

Family

ID=9967654

Family Applications (1)

Application Number Title Priority Date Filing Date
US135621A Expired - Lifetime US2225033A (en) 1936-04-09 1937-04-08 Television system

Country Status (3)

Country Link
US (1) US2225033A (de)
DE (1) DE756013C (de)
GB (1) GB475032A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2415390A (en) * 1941-09-30 1947-02-04 Crosley Corp Intermittent motion device
US2560994A (en) * 1948-04-05 1951-07-17 Color Television Inc Scanning system for motion picture films
US2590281A (en) * 1948-08-13 1952-03-25 Rca Corp Television film scanner
US2622147A (en) * 1947-09-10 1952-12-16 Emi Ltd Flying spot scanning of continuously moving film
US2718549A (en) * 1949-10-29 1955-09-20 Bell Telephone Labor Inc Continuous film motion projector for television cameras and film recorders

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2281166B (en) * 1993-08-16 1997-08-06 Rank Cintel Ltd Telecines

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL31494C (de) * 1929-07-19
GB433853A (en) * 1933-11-21 1935-08-21 John Logie Baird Improvements in or relating to television and like systems
FR47202E (fr) * 1934-09-04 1937-02-20 Loewe Opta Gmbh Procédé de transmission de télévision

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2415390A (en) * 1941-09-30 1947-02-04 Crosley Corp Intermittent motion device
US2622147A (en) * 1947-09-10 1952-12-16 Emi Ltd Flying spot scanning of continuously moving film
US2560994A (en) * 1948-04-05 1951-07-17 Color Television Inc Scanning system for motion picture films
US2590281A (en) * 1948-08-13 1952-03-25 Rca Corp Television film scanner
US2718549A (en) * 1949-10-29 1955-09-20 Bell Telephone Labor Inc Continuous film motion projector for television cameras and film recorders

Also Published As

Publication number Publication date
GB475032A (en) 1937-11-09
DE756013C (de) 1953-02-23

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